The present invention relates generally to eyeglass or spectacle frames of the type in which flexible tie members are used to hold the lenses in place on the frame.
Prior art frames may be divided into at least two categories: in a first catagory the rims are opened at their temple sides where they are connected together, such rims most often being of metal construction and shaped to accommodate the lenses; and in the second category, flexible threadlike ties attached to a rigid main frame structure are used to hold the lenses in place.
The present invention relates more particularly to this second category of frames wherein the rims are formed in part of flexible tie members.
Such frames are disclosed in British Pat. No. 775,293 in which each of the lenses is held in place on the main frame structure by means of a flexible tie anchored at its ends on the main frame structure.
The use of such flexible ties for holding the lenses in an eyeglass frame has required the selection of relatively rigid materials for the construction of the main frame structure, failing which by mere deformation of the overall frame structure the lenses may accidentally fall out of their respective rims. Heretofore the use of flexible ties to secure the lenses in place has meant that the provision of a main frame structure which may consist of a main cross bar but in any event is adapted to receive part of the peripheries of the lenses in order to properly secure them and to tighten the flexible ties around the rest of the peripheries of the lenses, and in addition to provide a support for the nosepieces.
Consequently, known frames of the second category though not heavy are of not insubstantial weight and require impractical arrangements for securing the ties and for receiving the peripheral parts of the lenses. Further, the presence of a main frame structure necessarily increases the cost of the resulting frame. Finally, the aesthetics of such a frame is marked by the presence of the main frame structure which often comprises relatively massive upper parts of both rims.